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Coordinatively Unsaturated Trinuclear Molybdenum-Sulfur Cluster Chelates with Dithiophosphinato Bridge.

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Our experimental findings that 1,2,4,5,7,8,10,1 l-octahydrobiscyclobuta[4,5]benzo[1,2-a : 1’,2’-e]cyclooctene 3 is
formed initially, and not the [2.2.2.2]cyclophane 4, is very
interesting, because 3 occurs as intermediate in the multistep synthesis of 4I5l, and 4 has already been obtained by
thermolysis of 3.
The novel synthetic route uia an “ortho-sulfone pyrolysis” not only offers the advantage of a small number of
rapid and simple steps, but also enables synthesis of dihydrocyclobutabenzene intermediates such as 3, which are
thus also conveniently accessible for other reactions. Furthermore, numerous unsymmetric phane-hydrocarbons
such as the pyrazinobenzophane 5 should now be accessible in an analogous way from the corresponding unsym-
metrical sulfones, whereas previous methods were restricted to symmetrical compounds of type 3 and 4. Fivefold and sixfold bracketed arenes-e.g. superphanes-including the corresponding dihydrocyclobutabenzene intermediates, should also be obtainable by this novel combination of cesium-catalyzed sulfide cyclization“] and orthosulfone pyrolysis.
Received: July 28, 1982 [Z110 IE]
German version: Angew. Chem. 94 (1982)922
The complete manuscript of this communication appears in:
Angew. Chem. Suppl 1982, 1956-1961
F. Vogtle, B. Klieser, Angew. Chem. 94 (1982)632;Angew. Chem. Int. Ed.
Engl. 21 (1982)618.
F. Vogtle, G. Hohner, Top. Curr. Chem. 74 (1978) 1.
F. Vogtle, L. Rossa, Angew. Chem. 91 (1979)534;Angew. Chem. Int. Ed.
Engl. 18 (1979)515;V. Boekelheide, R. A. Hollins, J. Am. Chem. Soc. 95
(1973)3201.
V. Boekelheide, R. Gray, Angew. Chem. 87 (1975)138;Angew. Chem. Int.
Ed. Enyl. 14 (1975) 107: J. Kleinschroth, H. Hopf, ibid. 91 (1979)336 and
18 (1979)329.
V. Boekelheide, G. Ewing, Tetrahedron Lett. 1978. 4245.
Bis[bis(trimethylsilyl)acetylenejdicarbonylchromium* *
By Karl Heinz Do&* and Jochen Muhlemeier
Pentacarbonyl[aryl(methoxy)carbene]chron~ium complexes 1 react with equimolar amounts of bis(trimethy1si1yl)acetylene 2 to give the metal-coordinated vinylketenes
3, which can be formally described as products of a headto-tail addition of the carbene and a carbonyl ligand to the
alkyne[41.In contrast, if the reaction is carried out with an
excess of alkyne (e. g. in the ratio 1 : 2 = 1 :2.2) in tert-butyl methyl ether, then, on heating, the uncoordinated vinylketene 4 and the title compound 5 are also obtained.
The deep-violet complex 5 , which is moderately sensitive to light and extremely sensitive to oxidation, was char[*] Priv.-Doz. Dr. K. H.Dotz, J. Muhlemeier
Anorganisch-chemisches lnstitut der Technischen Universitat Miinchen
Lichtenhergstrasse 4, D-8046 Garching (Germany)
[**I Vinylketenes, Part 4. This work was supported by the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrk-Part 3:
[I1
Angew. Chem. Int. Ed. Engl. 21 (1982) No. 12
Me3Si,
SiMej
O=C=C<
c = c’
Aryl‘ Cr(C013
O=C=C:
’
‘OMc
Mc3Si’
z
CEC/
Me3Si’
,SiMe3
Aryl
‘OMc
‘SiMc3
4
3
Aryl
c=c
SiMq
p-C6Hq-R (R
5
= H. Me. OMe.CF3)
acterized by total analysis and by spectroscopic methods[’]
[IR: v(C=O) 1965, 1904 cm-’ (n-hexane), v(C=C) 1705
c m - ’ (Nujol); ‘H-NMR: 6=0.28; MS: m/z=448 ( M + ) ,
392 ( M + - 2 CO), 222 ( M +- 2 C0-Me3Si--C=CSiMe,). In solution, bis(trimethylsilyl)acetylene is slowly
cleaved from the complex if not kept in the dark, thus ruling out coupling of the alkyne ligands in the complex. Information about the coordination of the alkyne ligands is
provided, in particular, by the I3C-NMR spectrum: The
signal of the C-atoms of the two CO-ligands appears at
6=258.9, that of the alkyne C-atoms at 6 = 197.8; such
downfield shifts (free alkyne: 6= 115.4) are regarded as a
criterion for the alkynes functioning as four-electron ligandsI6l, thus leading to the noble gas configuration of the
chromium in 5 . In contrast, the 29Si chemical shift
(6= - 7.4) is unsuited for investigation of the electron-donor capability of the alkyne, as is revealed on comparison
with
the
two-electron
alkyne
ligand
in
(CO),Fe(Me,Si-C=C-SiMe3)
(6= - 8.5)[91.
The bis(a1kyne)dicarbonyl complex 5 constitutes the
first satisfactorily characterized ternary alkyne-carbonyl
compound of chromium, after the synthesis of the tris(a1kyne)carbonyl complexes of molybdenum and tungsten
could so far not be extended to the lightest homologue.
Received: August 2, 1982 [ZI16 IE]
supplemented: October I I , 1982
German version: Angew. Chem. 94 (1982)936
The complete manuscript of this communication appears in:
Angeng. Chem. Suppl. 1982. 2023-2029
[I] K. H. Dotz, B. Trenkle, U. Schuhert, Angew. Chem. 93 (1981)296;Angew.
Chem. Int. Ed. Engl. 20 (1981)287.
[4] K. H. Dotz, B. Fugen-Koster, Chem. Ber. 113 (1980) 1449.
151 We thank Priv.-Doz. Dr. H. G. All and Priv.-Doz. Dr. F. R. Kreissl for recording the NMR spectra ([D,]-toluene, rel. int. TMS) and the mass spectrum.
161 J. L. Templeton, B. C. Ward, J. Am. Chem Soc. 102 (1980)3288.
191 K. H. Pannell, A. R. Bassindale, J. W. Filch, J. Organomet. Chem. 209
(1981)C65.
Coordinatively Unsaturated Trinuclear
Molybdenum-Sulfur Cluster Chelates
with Dithiophosphinato Bridge
By Helmut Keck. Wilhelm Kuchen*, Jurgen Mathow,
and Hartmut Wunderlich
We have found that by allowing Mo,S,-cluster dithiophosphinates l 1 I 1 to react with triphenylphosphane partial
[*]Prof. Dr. W. Kuchen, Dr. H. Keck, J. Mathow, Dr. H. Wunderlich
Institut fur Anorganische Chemie und Strukturchemie der Universitat
Universitatsstrasse 1 , D-4000 Dusseldorf (Germany)
0 Verlag Chemie GmbH, 6940 Wemheim, 1982
0570-0833/82/1212-0929 $ 02.50/0
929
desulfurization occurs leading to the coordinatively unsaturated, diamagnetic nonelectrolytes 2.
The Mo3 triangular plane remains intact both in the coordinative saturation of 2 and in reaction (I).
Received: July 7, 1981 [Z 402 IE]
German version: Angew. Chem. 94 (1982) 927
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1982. 1962- 1966
Consistent with this structure (Fig. l), the 31P('H)-NMR
spectrum of 2a exhibits three resonances in the intensity
ratio 1 :2 : 1 (0.03 M in CH2C1,; C?p= 123.2, 114.8, and 83.7,
rel. to 85% H3P04) and the FD-mass spectrum the molecular ion
+,m / z 1034, ref. to 98Mo).
([m
CAS Registry numbers:
la, 79594-15-3; lb, 79594-18-6; 2a, 83664-61-3; 2b, 83664-62-4; 3a, 8366463-5: 3b, 83664-64-6; PhrP, 603-35-0.
[ I ] H. Keck, W. Kuchen, J. Mathow, B. Meyer, D. Mootz, H. Wunderlich,
Angew. Chem. 93 (1981) 1019; Angew. Chem. Inr. Ed. Engl. 20 (1981)
975.
[2] P. J. Vergamini, H. Vahrenkamp, L. F. Dahl, J . Am. Chem. Sac. 93 (1971)
6327.
131 W. Beck, W. Danzer, G. Thiel, Angew. Chem. 85 (1973) 625; Angew.
Chem. I n / . Ed. Engl. 12 (1973) 582.
[4] A. Miiller, U. Reinsch, Angew. Chem. 92 (1980) 69; Angew. Chem. Inr. Ed.
Engl. 19 (1980) 72.
Chiral Silica Packings with L-Proline or
L-Hydroxyproline Bonded via Alkyl or Alkylbenzyl
Chains for the Separation of the Enantiomers of
a-Amino Acids by HPLC
Fig. I. Structure of the molybdenum(1V) cluster 2a in the crystal
The cluster contains the central unit M O ~ S ~ [ *As
- ~ ]in. l a ,
each of the M o atoms, which form a triangle, is chelated
by a dithiophosphinate moiety and capped trigonal-pyramidally by a sulfur atom. However, instead of the bridging S:- ligands, single sulfide bridges now occur. Two of
the Mo atoms are additionally linked to each other via a
dithiophosphinato bridge, and hence sulfur fulfills four
different bonding functions in the molecule. The formal
oxidation state of the metal atoms in 2a is the same as that
in l a . However, in contrast to all other trinuclear MoS
clusters the coordination number of the three Mo atoms in
cluster 2a is different: this is seven for one Mo atom and
eight for the other two Mo atoms. In consequence, the
coordinatively unsaturated compounds 2 can add, e. g. pyridine, to form [Mo3S4(R2PS&py] 3 (3a: R = E t ; 3b:
R = nPr) which upon heating is quantitatively released to
give 2 again. The different coordination state in 3 is expressed inter a h by a distinct high-field shift of the resonances in the 31P('H)-NMRspectrum. Hence, 3a also displays three resonances in the intensity ratio 1 :2 : 1, however, at 6p= 116.6, 114.1, and 80.9 (0.03 M in CH,CI,). As expected, the resonance of the chelate ligand bonded to the
originally coordinatively unsaturated molybdenum atom is
most strongly influenced: AtjP=6.6 ppm, relative to 0.7
and 2.8 ppm. Analogous situations are found when the resonances of 2b and 3b are compared.
Clusters 2 react with Ss or R2P(S)SzP(S)RZ( R = Et, nPr)
as sulfur donor to re-form 1 . Thus, reaction (1) reflects the
redox process
sf- + s + sz
930
0 Verlag Chemie GmbH. 6940 Weinheim, 1982
By Panayiotis Roumeliotis. Klaus K . Unger*,
Alexandre A . Kurganou, and Vadim A . Davankov
The separation of enantiomers by means of column liquid chromatography has been the subject of numerous reports"]. A favorite way of obtaining enantioselective supports consists in covalently bonding optically active ligands via a spacer to the surface of
We synthesized silicon compounds of the type
(EtO),Si-X-L-proline
and (EtO)3Si-X-L-hydroxyproline, which on reaction with LiChrosorb Si 100 (d,= 10 pm;
Merck) yielded chiral silica packings 1-4.
\'
1, X
2, X
3, X
C OOH
= -CH2= -(CH2)3= -(CHz)a-
4, X =
a, R
= H;
b, R
- , C H 3 * ~ C H * -
= OH
The concentration of surface functional groups
amounted to 3-4 pmol/m2. The supports were packed in
columns by the slurry technique and loaded with Cu'+
(copper acetate solution). Table 1 shows examples of the
separation of the enantiomers of a-amino acids[51.
The supports examined differ from each other in the
type of hydrophobic spacer X that is employed. a-Amino
acids with hydrophobic groups, e. g. Phe, Trp, Leu, Ile, Tyr,
show increasing retention with increasing hydrophobic
character of the spacer in the series of packings
4 > 3 > 2 > 1. Accordingly, the retention is controlled by
hydrophobic interactions. a-Amino acids with lower hydrophobicity exhibit a markedly complicated retention be-
[*] Prof. Dr. K. K. Unger, Dr. P. Roumeliotis
Institut fur Anorganische Chemie und Analytische Chemie der Universitat
Joh.-Joachim-Becher-Weg 24, D-6500 Mainz (Germany)
Dr. A. A. Kurganov, Prof. V. A. Davankov
Nesmejanov Institute of Organo-Element Compounds
Academy of Sciences, 117813, Moscow (USSR)
0570-0833/82/12/2-0930 $ 02.50/0
Angew. Chem. Int. Ed. Engl. 21 (1982) No. I2
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clusters, bridge, sulfur, coordinatively, unsaturated, trinuclear, molybdenum, chelate, dithiophosphinato
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